The present invention relates to electrical machines and more particularly to electrical machines such as switched reluctance electrical machines in which electrical current is injected in order to provide a motoring function or a generating function.
Electrical machines are utilised in a wide range of environments and for a large number of purposes. Of particular interest with regard to aspects of the present invention is utilisation of electrical machines within gas turbine engines. These electrical machines are utilised for provision of electrical generating capacity as well as in order to act as electrical motors for various functions. There is a desire to locate such electrical machines as closely as possibly and preferably embedded within the gas turbine engine. By such an approach complex mechanical transmission mechanisms are removed giving significant operational and efficiency benefits.
As indicated above such electrical machines can act as generators as well as starter motors for the gas turbine engine. The electrical machine in normal operation as indicated would generally act as an electrical generator but during such starting functions it will be understood that the electrical machine will temporarily act as a motor. Generation systems typically utilise power electronic converters to enable very high power density electrical machine technologies to be used. Such technologies include switched reluctance electrical machines. High densities enable further size and weight benefits to be achieved in comparison with traditional synchronous electrical machines. Additionally, the inherent direct electrical current interface allows parallel connection and sharing of electrical power generated by different spools of the gas turbine engine.